I married my ex husband in 82, child in 84, divorced 85. His daughter is 24, and wants to sponsor her father back to the US. Where do I start

If you are US citizen, first of all you need to marry him (again), then you will be eligible to file a petition for spouse visa.

Read here: How Do I Bring My Spouse (Husband or Wife) to Live in the United States? (http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=3e6c96981298d010VgnVCM10000048f3d6a1RCR D&vgnextchannel=4f719c7755cb9010VgnVCM10000045f3d6a1 RCRD)

I don't wish to re marry, can't his daughter who is a US citizen request his return? And if so how?

I don't wish to re marry, can't his daughter who is a US citizen request his return? and if so how?

Yes, she can do that too.. here the info How Do I Bring My Parents to Live in the United States? (http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=81c6194d3e88d010VgnVCM10000048f3d6a1RCR D&vgnextchannel=4f719c7755cb9010VgnVCM10000045f3d6a1 RCRD)

It takes about a year or less...